The objective of this research is to develop paradigm by which the child-rearing environment and the child's responding in that environment can be observed and recorded in detail. This is accomplished by having mother, father, and children come to the laboratory, an informal homelike apartment, for a series of half-days. Much of the structure and many of the events in these visits are of the participants' own making. Typical rearing functions and requirements are kept intact. Conditions allow and encourage usual routines, behavior, and emotions (eating, playing, learning, disciplining, resting, being happy, angry, upset, etc.). There is also an underlying experimental structure in the sessions. Standard events are introduced as naturally as possible in order to elicit certain classes of response. Families are selected for study based on a psychiatric screening (SADS): Normal families are those in which mother and father are without a psychiatric diagnosis. Maternal depression (bipolar, unipolar and minor depression) defines the clinical groups. The father's diagnosis in this group is allowed to vary; only schizophrenia and antisocial personality are excluded. Mother, 1 1/2- to 2-year-old, and 5- to 8-year-old sibling are the participants in the first series of sessions. In the followup two years later, father is included: also an unfamiliar (4-year-old) peer is present for a limited period. Situations within the sessions arrange participants in various dyads and triads, and in the total family group. All sessions are videotaped. Individual psychiatric assessments and psychological interviews and testing procedures are included in the procedures.